英和和英

出典:『Wikipedia』 (2011/05/13 22:52 UTC 版)

英語による解説

引用

The Perseids ( /ˈpɜrsiː.ɨdz/) is the name of a prolific meteor shower associated with the comet Swift-Tuttle. The Perseids are so-called because the point they appear to come from, called the radiant, lies in the constellation Perseus. The name derives in part from the word Perseides (Περσείδες), a term found in Greek mythology referring to the descendants of Perseus. The stream of debris is called the Perseid cloud and stretches along the orbit of the comet Swift-Tuttle. The cloud consists of particles ejected by the comet as it travels on its 130-year orbit. Most of the dust in the cloud today is around a thousand years old. However, there is also a relatively young filament of dust in the stream that was pulled off the comet in 1862. The rate of meteors originating from this filament is much higher than for the older part of the stream.